Monkey See, Monkey Do As Teams Copy McLaren’s ‘F-duct’

Formula 1 can be a case of monkey see, monkey do as everyone scrambles to catch up when someone invents a better mousetrap. We saw it last year with the ingenious rear diffusers Brawn GP and other teams used. It’s happening again this year with McLaren and the brilliant F-duct that Ferrari and others are trying to duplicate.

The so-called McLaren F-duct is a brilliant way of minimizing high-speed drag while on the straights while ensuring the rear wing generates effective amounts of downforce in corners. The system is said to give the McLaren MP4-25 race cars another 3 mph in the straights, an obvious advantage in a sport where success is measured in fractions of a second.

The effectiveness of the system remains to be seen, as several cars that don’t use it have proven to be fierce competitors. But some teams worry the F-duct might work and are building systems of their own. Chief among them is McLaren’s chief rival, Ferrari.

According to Racecar Engineering, Ferrari and defending constructors champions Mercedes (formerly known as Brawn GP) tested their own versions of the F-duct system last weekend at the Chinese Grand Prix. Midfield teams Sauber and Williams are said to be developing them as well. The Ferrari and Mercedes systems are markedly different in design from the McLaren system, but both seek the same result: Reduce high speed drag in the straights while maximizing downforce in the corners while keeping the air flowing smoothly.

Solving that equation has always required a compromise found only by repeated testing during practice sessions. But McLaren has found an answer that is beautiful in its simplicity. We ran it down before the season opener in Bahrain, but we’ll recap it here.

A small air scoop just ahead of the driver allows air to enter a tube that runs through the cockpit and the air intake above the driver’s head to the rear wing. From there it flows to the wing and passes through small slots to the back side of the wing, where the added energy can aid the airflow like the slats on a plane. This increases downforce in the corners.

The downside of increased downforce is, of course, increased drag. To minimize this drag, the driver can close the vent with his left knee, halting air flow to the rear wing. That essentially stalls the rear wing, thereby reducing drag and increasing speed on the straightaways.

Mercedes has built a version that features a small channel in the middle of the rear wing. It looks like a beefy center support, but it provides much the same result as the F-duct. Racecar Engineering says two openings on the lower deck of the wing feed the upper deck via exits on the rear of the wing element. It isn’t clear just how it works, and the team is still working on it.

To the casual observer, Ferrari’s system looks like McLaren’s but it’s actually different. The Ferrari F10, like the McLaren MP4-25, features a duct that runs along the “shark fin” on the engine cover to the rear wing. The system is still a work in progress, and there aren’t a lot of details on how it works. But instead of an air inlet on the nose like the McLaren, Ferrari uses air that’s drawn into the engine air intake above the driver’s head.

That is a significant departure from McLaren’s system because, like the Mercedes system, it requires no direct involvement from the driver. The reason for that is the McLaren system is, as they say, “all of a piece.” The F-duct is part of the monocoque — in other words, it is actually built into the chassis. That makes it very tricky for other team to duplicate because the rules require monocoques to be homologated before the rulemakers the Fédération Internationale d l’Automobile. For that reason, changes are difficult — and expensive — to make once the season is underway.

So if McLaren’s system actually works, everyone else will have to come up with something to counter it. And they’ll have to come up with a workaround, because they won’t be able to copy the F-duct exactly.

Photos: McLaren Mercedes Vodafone F1

This photo of a pit stop at the Chinese Grand Prix provides a good view of the F-duct system. You can see the small scoop on the nose of the car — just above the “f” in “Vodafone” — and the bright orange duct leading to the rear wing.

Here’s a better view of the F-duct on Lewis Hamilton’s car during the Australian GP.

Another shot from Australia that shows the duct leading the rear wing.